For example, there is a diversity antenna as an antenna apparatus such that same radio signal is received by two antennas, and the signal received from the antenna with superior radio wave condition is preferentially used.
Further, for example, a multimode antenna structure is known in which, by connecting a conductive connection element between two antenna elements, current flowing to feed point of one of two antenna elements is shunted, and the two antenna elements are electrically isolated.
Further, for example, an integrated-type flat-plate multi-elements and electronic equipment are also known in which, by forming a cutout unit in end of a ground pattern, coupling coefficient between two antenna elements can be lowered.
Further, for example, a compact-type portable terminal apparatus for radio reception is also known in which a variable reactance or switch is provided in a concave portion cut out in an edge of an upper grounding conductor, and by the switch or variable reactance, correlation is lowered between antenna elements provided in tip portion of a plurality of convexes on the upper grounding conductor.
Patent Document 1: International Publication Pamphlet No. WO 2008/131157 A1
Patent Document 2: Japanese Laid-open Patent Publication No. 2007-13643
Patent Document 3: Japanese Laid-open Patent Publication No. 2007-243455
However, in the above-described technology of the prior art, when the connection element is directly connected between two antenna elements, characteristic of the antenna element changes. Hence, by further providing a matching circuit in the antenna apparatus, the antenna apparatus can correspond to change of characteristic and can keep reception or transmission frequency within a prescribed range. However, when the matching circuit is further provided in the antenna apparatus, the number of components increases to this extent, and setting space of various elements and similar within the antenna apparatus is reduced. The increase in the number of components or reduction in setting space renders difficult achievement of reduced space or smaller size for the antenna apparatus.
Further, in the above-described technology of the prior art, when the cutout portion is provided in the end of the ground pattern or the concave portion is provided in the upper grounding conductor, if the area of the cutout or concave portion is equal to or greater than a predetermined value, the setting space of various elements or similar set on the ground pattern is reduced by the amount of the cutout or concave portion.
On the other hand, by making the characteristic of the antenna element such as the coupling coefficient, correlation, or similar between antenna elements equal to or greater than a predetermined value, reception characteristic of the antenna apparatus and similar can be improved as well.